A high-power transmitter with a high-Q antenna such as, for example, solid state fixed position VLF station transmitters, are susceptible to severe damage if the radio frequency (RF) input excitation to the transmitter is suddenly removed or drastically changed in frequency. As a result, the high energy stored in the high-Q antenna and the antenna impedance matching circuit is subsequently dissipated in the power amplifier output devices at a level well above the maximum rating of such power amplifiers, thereby causing massive power output device failures. This failure results from the energy stored in high-Q antennas.
A need has thus arisen for a circuit protection device for protecting power amplifiers utilized with RF transmitters in the event of a loss in RF input excitation to the transmitter.